The present invention relates to a rotary tool including a cutting blade and to a cutting apparatus comprising the same. More specifically, it relates to a rotary tool which needs to recognize the characteristic properties of the cutting blade of the rotary tool at the time of cutting; and to a cutting apparatus comprising the same.
A typical example of cutting apparatus comprising a rotary tool including a cutting blade is a dicer for cutting a semiconductor wafer along cutting lines arranged in a lattice pattern on the surface of the semiconductor wafer. In this dicer, a rotary tool having a thin (for example, about 15 xcexcm) ring plate-like cutting blade is fitted onto a rotary shaft which is rotated at a high speed. The cutting blade of the rotary tool which is rotated at a high speed is caused to work on the semiconductor wafer to cut it. In order to cut the semiconductor wafer with desired sufficiently high accuracy, it is important to position the cutting blade and the semiconductor wafer relative to each other with sufficiently high accuracy. Stated in more detail, it is important to align the center line in a thickness direction of the cutting blade with the center line of each of the cutting lines on the surface of the semiconductor wafer with sufficiently high accuracy. It is also necessary to set the interference depth (cutting depth) of the cutting blade in the semiconductor wafer to a fully accurate predetermined value. In order to carry out the relative positioning of the cutting blade and the semiconductor wafer with sufficiently high accuracy, it is necessary to recognize the characteristic properties such as thickness and outer diameter of the cutting blade with sufficiently high accuracy. The cutting blade of the rotary tool for dicing the semiconductor wafer is generally formed as an electrodeposition layer comprising abrasive diamond grains held by an electrodeposition metal. As is known among people skilled in the art, the existence of some error in the formation of the above electrodeposition layer cannot be avoided and some error inevitably exists in the characteristic properties such as thickness and outer diameter of the cutting blade. To cope with this, when a new rotary tool is set in the cutting apparatus, a semiconductor wafer is tentatively cut by the rotary tool and the cut state of the semiconductor is analyzed in detail to recognize the characteristic properties of the cutting blade based on the analytical results. Based on this information, the positioning of the cutting blade relative to the semiconductor wafer is controlled when the semiconductor wafer is to be actually diced.
Thus, the detailed analysis of the cut state of the semiconductor wafer by tentatively cutting the semiconductor wafer each time a new rotary tool is used is extremely troublesome and requires great skill.
It is a principal object of the present invention to make it possible to recognize the characteristic properties of a cutting blade in a rotary tool quickly and easily without the need for tentatively cutting a semiconductor wafer.
According to an aspect of the preset invention, there is provided a rotary tool including a cutting blade and an indicator showing the characteristic properties of the cutting blade. There is also provided a cutting apparatus on which the rotary tool is detachably mounted and which comprises a means of reading the indicator.
Preferably, the rotary tool includes a hub integrated with the cutting blade and the indicator is provided on the surface of the hub. The cutting blade is shaped like a thin annular plate which extends from the hub and the characteristic properties include at least one of the thickness of the cutting blade, the outer diameter of the cutting blade and the projecting length in a radial direction of the cutting blade from the periphery of the hub.
According to another aspect of the present invention, there is also provided a combination of a rotary tool including a cutting blade and a storage case for storing the rotary tool, wherein the storage case includes an indicator showing the characteristic properties of the cutting blade. There is also provided a cutting apparatus on which the rotary tool of the combination is detachably mounted and which comprises a means of reading the indicator.
Preferably, the rotary tool is composed of a thin ring plate-like cutting blade alone. The characteristic properties include at least one of the thickness of the cutting blade, the outer diameter of the cutting blade and the inner diameter of the cutting blade.
The indicator is preferably a bar code. The bar code is preferably printed on a tag affixed to the rotary tool. The cutting blade is composed of an electrode position layer containing abrasive diamond grains and preferably shaped like a thin ring plate. The reading means may be a bar code reader.